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Geology of the Bayan Obo iron-rare-earth-niobium deposits, Inner Mongolia, China

January 1, 1991

The plate tectonic setting, regional geology, and certain aspects of the economic geology of the iron-rare-earth-niobium ore bodies at Bayan Obo, Inner Mongolia, China, were studied by a team of geologists from the Tianjin Geologic Research Academy and the U.S. Geological Survey between 1987 and 1989. These ore bodies were formed by hydrothermal replacement of Middle Proterozoic dolomite in an intracontinental rift setting. A variety of veins and/or dikes that have a carbonatite-like mineralogy cut the footwall clastic rocks and migmatites. The hanging wall is a shale that has been converted to a K-metasomatite and has microcrystalline potassium feldspar as its principal constituent. This shale served as a scaling caprock that contained the chemical solutions that reacted with the dolomite and created the enormous concentration of mineralized rock in an 18-kilometer-long syncline. The rocks that host these ore bodies and the associated mineralized areas occur today as roof pendants in granitoid rocks of Permian age.

Citation Information

Publication Year 1991
Title Geology of the Bayan Obo iron-rare-earth-niobium deposits, Inner Mongolia, China
DOI
Authors L.J. Drew, M. Qingrun, S. Weijun
Publication Type Conference Paper
Publication Subtype Conference Paper
Series Title
Series Number
Index ID 70016851
Record Source USGS Publications Warehouse
USGS Organization